Nanostructure Thin Films of Titanium Dioxide Coated on Glass and Its Anti UV Effect for Living Organisms
Mohammad Hossein Habibi,
The increasing use of ultraviolet (UV) light in medicine, industrial environments, for cosmetic use, and even in consumer products necessitates that greater attention be paid to the potential hazards of this type of electromagnetic radiation. To avoid any adverse effects of exposure to this type of radiation, suitable protection filters were produced to block UV bands. Nanostructure composite and thin film of titanium dioxide coatings on glass have been prepared by the sol—gel method. TiO2 sol suspension was prepared by first adding titanium tetra isopropoxide (Ti(OPr)4 or TTP) to a mixture of ethanol and HCl (molar ratio TTP:HCl:EtOH:H2O = 1:1.1:10:10) and then adding a 2 wt.% solution of hydroxyl ethyl cellulose (HEC) as dispersant followed by of stirring. Precalcined TiO2 nanopowder was mixed with a sol and heat treated. Thin and composite films were deposited on the glass substrate (microscope glass slide) by spincoating them at ambient conditions. After drying, samples were heated to 500 °C. The resulting films were characterized by UV-Vis spectroscopy, X-ray diffraction (XRD) and Atomic Force Microscopy (AFM). The purpose of our study was to determine if thin and composite TiO2 films with ultraviolet light have any effect on the growth of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Bacillus species (Bacillus sp.) We have seen unusual results in which TiO2 thin and composite films protect E. coli, S. aureus and Bacillus sp from UV light. The survival of E. coli with UV alone was 3.2 % while with UV and TiO2 composite film was 91%. The UVabsorbing coatings are transparent, colorless, and exhibit high optical quality. The UV-protective coatings offer an easy method to protect the living organisms against UV.
Keywords: UV-absorbing, nanostructure, composite thin film, coatings on glass UV-protection, living organisms
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